second approach, better fitting what was agreed upon so far.
- pv_names are local to SEC-node, so not exporting via json and marking
them 'private'
- 2 devices for 2 temperature control loops, not one 'monster' device
which handles everything.
- read_status implemented
- write_target also updates the status (may be sensible to go to the core?)
- provide working stubs in case epics is not installed (-> testing possible)
- tested with the stubs.
- tests with real epics.
found problems:
in EpicsTempCtrl(EpicsDriveable) the read/write_<paramname> methods from
EpicsDriveable needed to be reimplemented. This should not be needed!
Change-Id: I9e4eeaff83114131d117c8f04fba758dfe22237b
